package core.wrap;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/**
 * 防止Xss的攻击
 * @author Administrator
 *
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
  HttpServletRequest orgRequest = null;

  public XssHttpServletRequestWrapper(HttpServletRequest request) {
    super(request);
    orgRequest = request;
  }

  /**
   * 覆盖getParameter方法，将参数名和参数值都做xss过滤。<br/>
   * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/>
   * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖
   */
  @Override
  public String getParameter(String name) {
    String value = super.getParameter(xssEncode(name));
    if (value != null) {
      value = xssEncode(value);
    }
    return value;
  }

  /**
   * 覆盖getHeader方法，将参数名和参数值都做xss过滤。<br/>
   * 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/>
   * getHeaderNames 也可能需要覆盖
   */
  @Override
  public String getHeader(String name) {
    String value = super.getHeader(xssEncode(name));
    if (value != null) {
      value = xssEncode(value);
    }
    return value;
  }

  /**
   * 将容易引起xss漏洞的半角字符直接替换成全角字符
   * 
   * @param s
   * @return
   */
  private static String xssEncode(String s) {
    if (s == null || s.isEmpty()) {
      return s;
    }
    StringBuilder sb = new StringBuilder(s.length() + 16);
    for (int i = 0; i < s.length(); i++) {
      char c = s.charAt(i);
      switch (c) {
      case '>':
        sb.append('＞');// 全角大于号
        break;
      case '<':
        sb.append('＜');// 全角小于号
        break;
      case '\'':
        sb.append('‘');// 全角单引号
        break;
      case '\"':
        sb.append('“');// 全角双引号
        break;
      case '&':
        sb.append('＆');// 全角
        break;
      case '\\':
        sb.append('＼');// 全角斜线
        break;
      case '#':
        sb.append('＃');// 全角井号
        break;
      default:
        sb.append(c);
        break;
      }
    }
    return sb.toString();
  }

  /**
   * 获取最原始的request
   * 
   * @return
   */
  public HttpServletRequest getOrgRequest() {
    return orgRequest;
  }

  /**
   * 获取最原始的request的静态方法
   * 
   * @return
   */
  public static HttpServletRequest getOrgRequest(HttpServletRequest req) {
    if (req instanceof XssHttpServletRequestWrapper) {
      return ((XssHttpServletRequestWrapper) req).getOrgRequest();
    }
    return req;
  }
}
